TREM-1 is an activating receptor expressed on monocytes, macrophages and neutrophils.
These cells play a central role in chronic inflammatory diseases by releasing cytokines and other mediators that drive inflammation. TREM-1 mRNA and protein expression is up-regulated in patients with RA and IBD, and TREM-1-positive cells accumulate at sites of inflammation, correlating with disease severity. Peptidoglycan-recognition-protein 1 (PGLYRP1) expressed primarily by activated neutrophils is a ligand for TREM-1 and mediate TREM-1 signalling upon binding.
In vitro, engagement of TREM-1 triggers secretion of pro-inflammatory cytokines including TNF, IL-8, and monocyte chemotactic protein-1. In addition, TREM-1 signalling synergizes with multiple Toll-like Receptors (TLR) to further boost pro-inflammatory signals. In turn, this up-regulates expression of TREM-1, leading to a vicious cycle amplifying the inflammation. Increasing evidence indicates that TLRs contribute to the development and progression of chronic inflammatory diseases such as RA and IBD.
WO 2013/120553 discloses humanized anti-TREM-1 mAbs which inhibit both human and cynomolgus TREM-1 function. However, the viscosity profile of anti-TREM-1 mAbs may hamper the manufacturing process to produce a drug product at >50 mg/ml and could limit the optimal dose setting in the clinic. High dosage (several mg/kg) of protein therapeutics is often needed to achieve an adequate clinical effect and since the vast majority of these therapeutics are administered by subcutaneous delivery, the consequence is that patient self-administration of the therapeutic is limited to volumes of <1.5 mL (Shire et al., J. Pharm. Sci. 2004, 93, 1390-1402). The development of high concentration protein formulations suitable for patient self-administration is a general obstacle for manufacturing and delivery when protein formulation results in high viscosity of the resultant solution.
Charge distribution of mAbs has been studied with regards to the effect on the viscosity behaviour of mAb solutions (Ydav et al., Mol. Pharmaceutics 2012, 9, 791-802). Also, weak non-specific charge interactions that persist in dilute solutions have been shown to influence the viscosity of concentrated mAb solutions (Connolly et al., Biophys. J., 2012, 103, 69-78.). The remedies to reduce the viscosity of mAb solutions have been to introduce site-directed charge swap mutations that disrupt direct charge-charge intermolecular interactions (Ydav et al., Mol. Pharmaceutics 2012, 9, 791-802) or the addition of salts or counter ions (Liu et al., J. Pharm. Sci. 2005, 94, 1928-1940; Yadav et al., J. Pharm. Sci. 2010, 99, 1152-1168; Yadav et al., J. Pharm. Sci. 2012, 101, 998-1011; Kanai et al., J. Pharm. Sci. 2008, 97, 4219-4227). The addition of salts and counter ions can, however, result in adverse effects for the patient in terms of hyper-osmolality of the administered solution.
Disclosed herein are TREM-1 antibodies generated by site-specific mutation of the CDR's of the WO 2013/120553 disclosed humanized anti-TREM-1 mAb 0170. The disclosed antibodies do not disrupt direct mAb intermolecular charge-charge self-interactions but do have a favourable viscosity profile and maintained target binding profile. The favourable viscosity profile allows drug product to be produced at high concentrations that could be essential for therapeutic and pharmaceutical use. Such antibodies may have a substantial impact upon the quality of life of individuals with sepsis or a chronic inflammatory disease such as rheumatoid arthritis, psoriatic arthritis and inflammatory bowel disease.